In prenatal diagnostics, placenta growth factor (PLGF) testing is the newest innovation in diagnosing pre-eclampsia, a hypertension disorder affecting 5% to 8% of pregnancies. PLGF testing allows for early recognition of pre-eclampsia, opening a greater variety of treatment and monitoring options for mother and child. Current testing only recognizes the condition after onset. While symptoms do not present until 20 weeks, testing can evaluate predisposition for pre-eclampsia, which is highly treatable.
PLGF, produced by the placenta during pregnancy, is a valuable marker for fetal-growth progress because it is a potent angiogenic factor. Monitoring PLGF levels allows medical professionals to evaluate intrauterine growth and develop strategies to address complications. The new tests identify PLGF in blood earlier and more effectively than do traditional testing measures.
Testing for pre-eclampsia
Pre-eclampsia is characterized by high blood pressure and elevated protein levels in urine during pregnancy. Early testing for pre-eclampsia is essential in a pregnancy to prevent other more serious complications (e.g., eclampsia and HELLP syndrome [H = hemolysis; EL = elevated liver enzymes; LP = low platelet count]). If left untreated and unmonitored, it can cause important growth factors to act irregularly, thus leading to increased risk of fetal malnutrition and altered growth patterns. PLGF testing builds upon currently used testing and monitoring tools for pre-eclampsia; traditionally, testing has been part of a battery of tests administered during the prenatal phase. These broad tests are designed to look for a number of possible conditions or complications; doctors look for symptoms — and biological markers, two of which are elevated blood pressure and protein in the patient’s urine. If there are monitored irregularities in these, the doctor will order further tests (e.g., fetal ultrasounds, blood testing, or a biophysical profile).
In a normal pregnancy, angiogenesis, and vascular transformation lead to normal placental development, whereas pre-eclamptic pregnancies are subject to abnormal angiogenesis and vascular transformation. Since PLGF is a factor in angiogenesis, testing of the PLGF levels at 15 weeks allows a doctor to determine whether a patient is at high risk, since the PLGF level in a patient with pre-eclampsia will be lower than average PLGF levels during a normal pregnancy. Catered to the patient’s risk level, a doctor can devise a treatment plan and continue consistent monitoring. Failure to detect pre-eclampsia can trigger severe complications during and after a pregnancy. The complications can lead to eclampsia, a condition categorized by severe headaches, vision problems, and — after further progression — possible death for the woman and her baby.
Causes, symptoms, and markers
The cause(s) of pre-eclampsia are still unclear. Research has found numerous possibilities but nothing definitive. Data shows traditional pregnancy risk factors (e.g., obesity, advanced age) increase the chances of a woman having pre-eclampsia during pregnancy. Studies show women who have pre-eclampsia once are prone to have it in subsequent pregnancies. The symptoms of pre-eclampsia include severe headaches, nausea, or vomiting, increased weight gain, and increased agitation. The onset of pre-eclampsia can be sudden or, in some cases, gradual; it usually begins to present symptoms around the 20th week of pregnancy.
Many physical markers for pre-eclampsia are similar to conditions encountered during a routine pregnancy — and this is why proper prenatal care and testing is vital. With early detection, a doctor can recommend a treatment strategy for a healthy pregnancy and successful delivery based on a patient’s particular stage of pregnancy. While the symptoms can be treated and monitored to ensure the prescribed strategy is working, the only “cure” for pre-eclampsia is delivery of the baby. In severe cases, early inducement of labor or C-sections is necessary to ensure safe delivery for the mother and/or baby, following which the patient’s blood pressure should return to normal. If not, there may be a risk of eclampsia and/or further complications.
Other possible complications
Pre-eclampsia can be manifested by an extremely dangerous condition termed HELLP syndrome; failure to treat it can lead to death. The longer it takes for a doctor to recognize pre-eclampsia, the higher the risk for the 15% of women who have it, and then develop and suffer with HELLP. Babies born at a weight of more than 200 grams with HELLP will have a similar mortality rate to babies born without HELLP, but a baby born under 200 grams can face severe complications. PLGF testing can identify the condition early, allowing for enhanced monitoring of the onset of conditions such as HELLP as well as increased treatment options — thus, the health and safety of the mother and the baby can be greatly enhanced.
Alfred Janetzko, PhD, is the director of R&D of DRG Instruments GmbH, Marburg, Germany, a wholly-owned subsidiary of DRG International.